Savestate: Implement Inline Visual Explanations with Intelligent Pedagogical Filtering and remove legacy inpainting

docs: Add implementation plan for Inline Visual Explanations

docs: Add design spec for Inline Visual Explanations

Savestate: Add design spec for Nano Banana 2 integration

Savestate: Implement 3D Isometric Detective Board UI, fix mobile report formatting, increase report length constraint

docs: add dynamic background spec

docs: add deep research canvas implementation plan

docs: add Deep Research Canvas design spec

docs: add deep research design spec